Subaru tops crash avoidance tests

CNBC's Phil LeBeau test drives one the most popular safety features for new vehicles to see if it actually works.

Subaru placed two models atop a list of seven vehicles with collision avoidance systems that rate among the best in the industry.

The rankings follow crash tests conducted by the Insurance Institute for Highway Safety, measuring how quickly vehicles alert drivers about possible rear-end collisions and whether vehicles avoid a crash or reduce their speed by at least 5 mph.

"Front crash prevention systems can add a thousand dollars or more to the cost of a new car," said David Zuby, chief research officer at IIHS. "Our new ratings let consumers know which systems offer the most promise for the extra expense."

The most recent crash data from the Department of Transportation shows there were 1.7 million rear-end accidents in the U.S. in 2011.

Rear-end accidents accounted for 6 percent of crashes with fatalities and 31 percent of those that resulted in injuries.

IIHS crash test

The Insurance Institute looked at 74 midsize cars and SUVs, 18 of which also have auto-brake systems. Of those 18 models, 7 received a "superior" rating.

Front crash prevention "superior" ratings

Subaru Legacy

Subaru Outback

Cadillac ATS

Cadillac SRX

Mercedes-Benz C-Class

Volvo S60

Volvo XC60

Fifteen other models were rated as "advanced" since they helped warn drivers and did slow down vehicles. However, those systems did not perform as well as the models rated as "superior."

Subaru and Cadillac excel

The Subaru EyeSight collision avoidance system is the only system with auto brakes that prevented the vehicles from hitting the target when travelling at 25 mph and 12 mph.

Cadillac's Automatic Collision Preparation system helped the ATS and SRX models avoid hitting the target in the 12 mph tests.

Zuby said the tests are an early benchmark to measure the effectiveness of systems becoming more common. "We want to help get the most effective systems in as many vehicles as soon as possible."

Safety sells

Volvo discovered long ago how important safety features are to driving sales. For years, the Swedish brand was seen as having the safest vehicles in the world.

Given that background, it's not surprising to see the Volvo S60 and XC60 among the seven models rated as superior.

"There is no doubt that safety sells," said Michael Robinet with IHS Automotive. "Vehicle manufacturers around the world understand that the safety of drivers and passengers are important so we have had a plethora of new innovations in the vehicle to keep everybody safer."

Collision avoidance technology has become an increasingly popular safety feature for automakers to highlight in car ads. As the technology becomes more advanced, more vehicles are expected to incorporate auto brakes to help prevent accidents.